I've been working sporadically on SilentE for the past few days. Everything is taking much longer than I expected. But there have been a few... exciting moments.
For instance, the first battery I tried to install in the rear pack shorted. (That's number 3, for those following along on the chart.) There will be two batteries hidden under the hatchback floor (numbers 3 and 6), and so I put all their connections on before installing them. The gap under the rear seat is barely big enough, and the cables bent upwards. Of course, the terminal covers only protect the tops, so all that was necessary to short the battery was for one cable to twist... and it did.
There were lots of sparks, and the terminal clamps had some small gouges melted in. No biggie. It occurred a cable's length away from me, so I didn't feel a thing. But the regulator installed on top of the battery did. It's red LED came on and stayed on. A quick email to the EV list indicated that this is the undervoltage light: it's supposed to stay on, so you can tell which battery got low enough to possibly damage it. Disconnecting the regulator and reconnecting it fixed it, so the battery is (probably) fine. I slid it into place and continued with the install.
I had to bend a few regulator terminals to get them to go under the dip where the rear seat turns into the hatch. (Nathan claims dropping the battery box an extra inch will be "too hard". Wimp.;-)) But I eventually managed to get everything in except for the final two batteries: the front two rows on the passenger's side (numbers 1 and 2).
My terminal covers are hinged for easy access. I didn't notice that the other end of the cable I was about to connect had slipped under the hinge for the cable from 3 to 4. (That's the long cable, going from one of the hidden batteries to the front of the pack.) As I pressed the clamp to the number 2 positive terminal, a shower of sparks erupted. Even though I was touching the clamp, I felt nothing. I instinctively pulled it off, stopping the sparks. Of course, the giant white cloud of vaporized lead didn't escape my attention, either. My daughter Tatiana (who was acting as my safety inspector) and I abandoned the open garage to let the fan take care of the ugly stuff.
My hand had been splattered with dark spots. They washed off easily. We threw some darts, then went back out to inspect the damage.
The battery had been splattered, radially, with lead. Some of it had gone toward the regulator, of course. There's no way to test if it's okay until I finish hooking up the charger. Part of the terminal had melted (or vaporized away); that one will have a worse connection than all the rest. The terminal clamp had vaporized into a cone. Rather than try to make it work, and possibly cripple $7000 and two years of work for the sake of a $3 part, I swapped it for a new one. Some filing of the misshapen terminal made everything fit; I may have lost as much as 10% of the conductive area. And, of course, the regulator on the inaccessible number 3 battery has its red light stuck on. That'll turn off when I get the pack connected and start charging. Meanwhile, I think that YellowTop could run the LED for years before it went dead.
I called the Interstate store where I purchased the batteries. No, there's no way to melt a new terminal on. Solder might work, but I'd need to use something designed to handle the high current (up to 400 amps or so). A new battery would be the best bet. Alas, no; the warrant doesn't cover stupidity.
I decided to stick with what I've got for now. I don't intend to drive this like a hot rod; I don't think I'll have any trouble.
The last battery wouldn't fit. I eventually removed the handles from the center batteries (numbers 4 and 5) to get the extra two millimeters required. Then I connected everything. The only missing pieces are the cables to the front.
The next day, with very little time, I tried to get the front pack and charger connected. After a quick teleconference with Nathan, I found and moved a few wires. Then I spent an hour or so making sure the charger was going to be set up correctly. Eri and I spent some time drawing how things should work. Then I started on the front pack. The batteries are so tight you can't drop them in individually. You have to tilt them in together. I was missing a few terminals, so I quit for the day and spent some time with my family.
Step: 2006-07-24
At 11PM (past bedtime), I went out to do whatever I could do. Baby steps, remember.
I made the correct length of cables for each of the batteries in the front pack. I figured out where the regulators would go. I attached the regulators to their batteries. It's too dark to finish making the cables, or to wire everything up; I'll try to do that when I get home tomorrow.
Step: 2006-07-25 I hooked up the front battery pack. There's a particular connection that has to twist and bend through a right angle; it's going to cause us trouble later on, I can tell. I also added two fuses to the wiring, hooked up the emergency disconnect circuit breaker, and verified the wiring for the charger.
While hooking up the breaker, I got shocked. I couldn't figure out why it should happen; the breaker was closed, I wasn't expecting any current across the terminals. Another good reason to wrap your tools! (This time, the short was from the breaker terminal, through the wrench, through my hand to my wrist, to the other breaker terminal. If I had wrapped the wrench, it wouldn't have conducted.)
No damage, nothing major. But I decided to check the conductivity of the breaker and fried my voltmeter. D'oh! This incident wins me the moniker "Spark Lad" on the EV Discussion List.
Step: 2006-07-26 I wired everything together today. I had sufficient already-crimped wire to get the job done with just a couple of extra clamp-on battery terminal clamps. Nathan's coming over tomorrow to check everything and add the last safety components; we expect to take our maiden voyage that evening after work.